The long-term objectives of this research are to determine what limitations are imposed on auditory analysis by otopathologies underlying sensorineural hearing loss, how those limitations are influenced by frequency selective hearing losses, and whether or not different limitations are imposed by different sensorineural etiologies. Limitations in auditory analysis will be inferred from psychophysical measures of interference (masking) between one sound and another. To obtain estimates of limitations in auditory frequency analysis, frequency masking patterns between tones will be measured. Levels of remote-frequency tones will be determined that just mask fixed-intensity, fixed-frequency, probe tones; the resulting masking patterns are called psychophysical tuning curves. To obtain estimates of limitations in auditory temporal analysis, temporal masking patterns will be measured. Levels of temporally disparate tones will be determined that just mask fixed-intensity, fixed-frequency, probe tones; the resulting masking patterns are called isoprobe temporal masking curves. Masking patterns will be measured with forced-choice adaptive procedures in a nonsimultaneous (forward) masking paradigm. Both frequency masking patterns and temporal masking patterns will be obtained in the same sensorineural hearing-impaired listeners using probe tones at various sensation levels and frequency regions to determine whether suprathreshold sensory excitations are more vulnerable to interference in the sensorineural-impaired ear than in the normal-hearing ear. Results will be related to psychophysical models of auditory analysis and hearing impairment. Since the measures of auditory analysis proposed here emphasize concepts of interference between one sound and another, the results of this research will have practical implications for preventative, diagnostic, and habilitative aspects of health care for the hearing-impaired patient. In addition, this research will aid our understanding of the mechanisms by which diseases of the ear affect the ability of human listeners to process the sounds around them, particularly speech.